BD8649EFV-E2 Rohm Semiconductor, BD8649EFV-E2 Datasheet - Page 7

• Manufacturer Part Number: BD8649EFV-E2
• Description: IC SWITCHING REG 3A HTSSOP-B20
• Manufacturer: Rohm Semiconductor
• Series: -r
• Type: Step-Down (Buck), PWM - Current Moder

Specifications of BD8649EFV-E2

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 1 V ~ 12.6 V
• Current - Output: 3A
• Frequency - Switching: 100kHz ~ 600kHz
• Voltage - Input: 4.5 V ~ 18 V
• Operating Temperature: -20°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 20-VSSOP (0.173", 4.40mm Width)
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

BD8649EFV
© 2010 ROHM Co., Ltd. All rights reserved.
www.rohm.com
3 Under voltage lock out protection (UVLO)
As for BD8649EFV, the power-supply voltage decrease detection protection circuit is built in.
It the input voltage decrease below the UVLO voltage (4.0V typ), the device state changes to the standby mode (Moreover,
to prevent the chattering of the output) hysteresis width of 300mV(typ) has been installed in the UVLO cancel voltage.
4 RT terminal open/short protection function (RTO/RTS)
RT terminal opening/short protection function prevents the clock from abnormal oscillation.
If RT terminal open/short protection function is detected, output voltage changes to low level and is fixed.
5 Soft start time-out function
If VSS doesn't exceed VSSTH within 75msec (typ) since a soft start began, BD8649EFV controls an off latch.
Vo is fixed in a low level.
6 Thermal shut down function
Thermal shut down circuit (TSD circuit) is built into BD8649EFV. When the temperature of the chip exceeds Tjmax=175, the
DC/DC converter is fixed in a low voltage.
TSD function is aimed to shut down IC from thermal reckless driving under an abnormal state to exceed Tjmax=150.
It aims at neither protection nor the guarantee of the set. Therefore, please do not use this function to protect the set.
7 Over current protection function
The over current protection function has been achieved by limiting the current that flows on high side MOSFET.
The current is controlled in every one cycle of the switching frequency. When an abnormal state continues, the output is
fixed in a low level.
8 Error detection (off latch) release method
BD8649EFV enters the state of an off latch when the protection function operates.
To release the off latch state, VIN terminal voltage should be changed to less than UVLO level (=4.0V [typ] ) once time.
SS terminal
0V
Fig.15 Soft start time-out
7/13
about 64msec（typ）
V
SSTH
Technical Note
2010.09 - Rev.A